In Detroit at Packard, Walter became involved in a very special Project. Captain Lionel M.
Woolson, the Chief Aeronautical Engineer and Dipl.Ing., Hermann I.A. Dorner, a diesel engine inventor from Hanover, Germany,
designed the Packard diesel with the help of Packard engineers and Dorner's assistant, Adolph Widmann. Walter worked with
Woolson and Marvin Steele, the assistant engineer.
The historic first flight of the Packard diesel engine took place on September 19, 1928, at the
Packard proving grounds, Utica, Michigan. But the first unofficial test was made the night before. Walter was given the distinction of
flying the world's first diesel powered airplane flight.